arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.01358cond-mat.mes-hall
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基于Su-Schrieffer-Heeger模型的Poor man拓扑量子门

Poor man's topological quantum gate based on the Su-Schrieffer-Heeger model

Péter Boross, János K. Asbóth, Gábor Széchenyi, László Oroszlány, András Pályi

摘要:

量子系统的拓扑性质可以保护信息不受环境噪声的影响,从而大大提高它们在量子信息处理中的潜力。拓扑保护量子门的大多数建议是基于多体系统,例如,分数量子霍尔态、奇异超导体或相互作用自旋的集合,具有固有的概念复杂性。在这里,我们提出并研究了拓扑保护的量子门,基于一维单粒子紧束缚模型,称为Su-Schrieffer-Heeger链。所提出的$Y$门作用于由三条链组装而成的Y结的二维零能量子空间中,并且基于支持零能量模式的缺陷的空间交换。通过数值模拟,我们证明了该门对跳跃无序是鲁棒的,但被破坏的现场能量的无序。然后,我们表明,这种鲁棒性是拓扑保护,它产生的联合后果的手征对称性,时间反演对称性和空间分离的零能量模式绑定到缺陷。这种设置很可能不会导致实际的量子计算机,尽管如此,它确实提供了有价值的见解,拓扑量子计算的方面作为一个基本的极小模型。由于该模型是非相互作用和非超导的,因此可以通过实验研究其动力学,例如,使用耦合的光波导。

英文摘要:

Topological properties of quantum systems could provide protection of information against environmental noise, and thereby drastically advance their potential in quantum information processing. Most proposals for topologically protected quantum gates are based on many-body systems, e.g., fractional quantum Hall states, exotic superconductors, or ensembles of interacting spins, bearing an inherent conceptual complexity. Here, we propose and study a topologically protected quantum gate, based on a one-dimensional single-particle tight-binding model, known as the Su-Schrieffer-Heeger chain. The proposed $Y$ gate acts in the two-dimensional zero-energy subspace of a Y junction assembled from three chains, and is based on the spatial exchange of the defects supporting the zero-energy modes. With numerical simulations, we demonstrate that the gate is robust against hopping disorder but is corrupted by disorder in the on-site energy. Then we show that this robustness is topological protection, and that it arises as a joint consequence of chiral symmetry, time-reversal symmetry and the spatial separation of the zero-energy modes bound to the defects. This setup will most likely not lead to a practical quantum computer, nevertheless it does provide valuable insight to aspects of topological quantum computing as an elementary minimal model. Since this model is non-interacting and non-superconducting, its dynamics can be studied experimentally, e.g., using coupled optical waveguides.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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